The present invention relates to a medical image processing apparatus for processing a medical image, a medical image processing method, its program and a recording medium on which the program is recorded.
For diagnoses of patients in the field of medical treatment, there have been used medical image radiographing apparatuses such as an X-ray radiographing apparatus employing a radiation such as X-ray, RI (Radio Isotope) apparatus, CR (Computed Radiography) apparatus, CT (Computed Tomography) apparatus, a supersonic radiographing apparatus and MRI (Magnetic Resonance Imaging) apparatus.
Images obtained through radiographing by the medical image radiographing apparatus have been converted from analog data in radiographing into digital data through a certain sampling, then, have been subjected to image processing such as frequency processing to be stored as processed image data, and a monitor which outputs on its screen and an imager wherein a film is exposed to light have been used to output the processed image data.
However, in the conventional medical image radiographing apparatus, images obtained through radiographing have been stored after being subjected to a certain sampling. Therefore, when outputting to an outputting apparatus which is different in terms of characteristics such as a type, an apparatus model and resolution, the stored image data are image-processed after being subjected to resolution conversion so that the image data may match each outputting apparatus, and thereby the image-processed image data are outputted. Thus, convertion of resolution is applied at least two times, and image deterioration was not avoided.
For example, when conducting resolution conversion, thinning processing and interpolation processing have deteriorated images. The “resolution conversion” here may be both of resolution gaining operation and resolution reducing operation.
The first subject of the invention is to prevent deterioration of medical images and to output medical images for each outputting apparatus.
Further, in the medical field in recent years, there has been developed a medical image processing apparatus which conducts various types of image processing on medical images inputted as digital images by various types of medical image radiographing apparatuses such as CT (Computed Tomography) apparatus employing radiation and MRI (Magnetic Resonance Imaging) apparatus and by various types of medical image input apparatus such as a medical image reading apparatus like CR (Computed Radiography), and displays on a monitor such as CRT, or outputs on a film. By observing images visualized to become easy to be seen by the medical image processing apparatus of this kind, a doctor can diagnose exactly.
In the aforementioned medical image processing apparatus, analog image data inputted from a medical image input apparatus are stored as original image data in general, and then, the original image data are subjected to sampling for conducting image analysis to generate reduction digital image data at a prescribed reduction rate. Incidentally, the purpose of generating reduction image data is to shorten the time required for the image analysis, and in the image analysis wherein reduction image data are used, it is possible to establish the reduction rate which is mostly the same as that in the occasion where the original image data are used.
Since the medical images are those obtained by radiographing various regions such as abdomen and breast with various medical image radiographing apparatuses such as CT and MRI, as stated above, an area (hereinafter referred to as a region of interest) to be looked by a doctor for each region or for each radiographing condition such as a radiographing method varies. For example, even in the case of images wherein the same breast is radiographed, a position and a shape of a region of interest vary and its information amount also varies, in the case of the radiographing method of simple radiographing to radiograph from the front side and of tomography to radiograph a tomogram. However, in the course of generation of the conventional reduction image data, the prescribed sampling condition is applied to all images, namely, reduction is made for all images at the prescribed reduction rate, without coping with the circumstances mentioned above. Therefore, its reduction rate does not always give efficient image analysis depending on radiographing conditions such as regions to be radiographed and radiographing methods, and there has sometimes been an occasion to lower accuracy of processing of image analysis or to lower the processing speed.
The second subject of the invention is to provide a medical image processing apparatus wherein sampling conditions corresponding to radiographing conditions are prepared in advance, and efficient image analysis can be conducted.